ld/plugin.c

   1 /* Plugin control for the GNU linker.
   2    Copyright 2010, 2011 Free Software Foundation, Inc.
   3
   4    This file is part of the GNU Binutils.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software
  18    Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
  19    MA 02110-1301, USA.  */
  20
  21 #include "sysdep.h"
  22 #include "libiberty.h"
  23 #include "bfd.h"
  24 #include "bfdlink.h"
  25 #include "bfdver.h"
  26 #include "ld.h"
  27 #include "ldmain.h"
  28 #include "ldmisc.h"
  29 #include "ldexp.h"
  30 #include "ldlang.h"
  31 #include "ldfile.h"
  32 #include "plugin.h"
  33 #include "plugin-api.h"
  34 #include "elf-bfd.h"
  35 #if !defined (HAVE_DLFCN_H) && defined (HAVE_WINDOWS_H)
  36 #include <windows.h>
  37 #endif
  38
  39 /* Report plugin symbols.  */
  40 bfd_boolean report_plugin_symbols;
  41
  42 /* The suffix to append to the name of the real (claimed) object file
  43    when generating a dummy BFD to hold the IR symbols sent from the
  44    plugin.  For cosmetic use only; appears in maps, crefs etc.  */
  45 #define IRONLY_SUFFIX " (symbol from plugin)"
  46
  47 /* Stores a single argument passed to a plugin.  */
  48 typedef struct plugin_arg
  49 {
  50   struct plugin_arg *next;
  51   const char *arg;
  52 } plugin_arg_t;
  53
  54 /* Holds all details of a single plugin.  */
  55 typedef struct plugin
  56 {
  57   /* Next on the list of plugins, or NULL at end of chain.  */
  58   struct plugin *next;
  59   /* The argument string given to --plugin.  */
  60   const char *name;
  61   /* The shared library handle returned by dlopen.  */
  62   void *dlhandle;
  63   /* The list of argument string given to --plugin-opt.  */
  64   plugin_arg_t *args;
  65   /* Number of args in the list, for convenience.  */
  66   size_t n_args;
  67   /* The plugin's event handlers.  */
  68   ld_plugin_claim_file_handler claim_file_handler;
  69   ld_plugin_all_symbols_read_handler all_symbols_read_handler;
  70   ld_plugin_cleanup_handler cleanup_handler;
  71   /* TRUE if the cleanup handlers have been called.  */
  72   bfd_boolean cleanup_done;
  73 } plugin_t;
  74
  75 /* The master list of all plugins.  */
  76 static plugin_t *plugins_list = NULL;
  77
  78 /* We keep a tail pointer for easy linking on the end.  */
  79 static plugin_t **plugins_tail_chain_ptr = &plugins_list;
  80
  81 /* The last plugin added to the list, for receiving args.  */
  82 static plugin_t *last_plugin = NULL;
  83
  84 /* The tail of the arg chain of the last plugin added to the list.  */
  85 static plugin_arg_t **last_plugin_args_tail_chain_ptr = NULL;
  86
  87 /* The plugin which is currently having a callback executed.  */
  88 static plugin_t *called_plugin = NULL;
  89
  90 /* Last plugin to cause an error, if any.  */
  91 static const char *error_plugin = NULL;
  92
  93 /* State of linker "notice" interface before we poked at it.  */
  94 static bfd_boolean orig_notice_all;
  95
  96 /* Original linker callbacks, and the plugin version.  */
  97 static const struct bfd_link_callbacks *orig_callbacks;
  98 static struct bfd_link_callbacks plugin_callbacks;
  99
 100 /* Set at all symbols read time, to avoid recursively offering the plugin
 101    its own newly-added input files and libs to claim.  */
 102 bfd_boolean no_more_claiming = FALSE;
 103
 104 /* List of tags to set in the constant leading part of the tv array. */
 105 static const enum ld_plugin_tag tv_header_tags[] =
 106 {
 107   LDPT_MESSAGE,
 108   LDPT_API_VERSION,
 109   LDPT_GNU_LD_VERSION,
 110   LDPT_LINKER_OUTPUT,
 111   LDPT_OUTPUT_NAME,
 112   LDPT_REGISTER_CLAIM_FILE_HOOK,
 113   LDPT_REGISTER_ALL_SYMBOLS_READ_HOOK,
 114   LDPT_REGISTER_CLEANUP_HOOK,
 115   LDPT_ADD_SYMBOLS,
 116   LDPT_GET_INPUT_FILE,
 117   LDPT_RELEASE_INPUT_FILE,
 118   LDPT_GET_SYMBOLS,
 119   LDPT_GET_SYMBOLS_V2,
 120   LDPT_ADD_INPUT_FILE,
 121   LDPT_ADD_INPUT_LIBRARY,
 122   LDPT_SET_EXTRA_LIBRARY_PATH
 123 };
 124
 125 /* How many entries in the constant leading part of the tv array.  */
 126 static const size_t tv_header_size = ARRAY_SIZE (tv_header_tags);
 127
 128 /* Forward references.  */
 129 static bfd_boolean plugin_notice (struct bfd_link_info *,
 130                                   struct bfd_link_hash_entry *, bfd *,
 131                                   asection *, bfd_vma, flagword, const char *);
 132
 133 #if !defined (HAVE_DLFCN_H) && defined (HAVE_WINDOWS_H)
 134
 135 #define RTLD_NOW 0      /* Dummy value.  */
 136
 137 static void *
 138 dlopen (const char *file, int mode ATTRIBUTE_UNUSED)
 139 {
 140   return LoadLibrary (file);
 141 }
 142
 143 static void *
 144 dlsym (void *handle, const char *name)
 145 {
 146   return GetProcAddress (handle, name);
 147 }
 148
 149 static int
 150 dlclose (void *handle)
 151 {
 152   FreeLibrary (handle);
 153   return 0;
 154 }
 155
 156 #endif /* !defined (HAVE_DLFCN_H) && defined (HAVE_WINDOWS_H)  */
 157
 158 /* Helper function for exiting with error status.  */
 159 static int
 160 set_plugin_error (const char *plugin)
 161 {
 162   error_plugin = plugin;
 163   return -1;
 164 }
 165
 166 /* Test if an error occurred.  */
 167 static bfd_boolean
 168 plugin_error_p (void)
 169 {
 170   return error_plugin != NULL;
 171 }
 172
 173 /* Return name of plugin which caused an error if any.  */
 174 const char *
 175 plugin_error_plugin (void)
 176 {
 177   return error_plugin ? error_plugin : _("<no plugin>");
 178 }
 179
 180 /* Handle -plugin arg: find and load plugin, or return error.  */
 181 int
 182 plugin_opt_plugin (const char *plugin)
 183 {
 184   plugin_t *newplug;
 185
 186   newplug = xmalloc (sizeof *newplug);
 187   memset (newplug, 0, sizeof *newplug);
 188   newplug->name = plugin;
 189   newplug->dlhandle = dlopen (plugin, RTLD_NOW);
 190   if (!newplug->dlhandle)
 191     return set_plugin_error (plugin);
 192
 193   /* Chain on end, so when we run list it is in command-line order.  */
 194   *plugins_tail_chain_ptr = newplug;
 195   plugins_tail_chain_ptr = &newplug->next;
 196
 197   /* Record it as current plugin for receiving args.  */
 198   last_plugin = newplug;
 199   last_plugin_args_tail_chain_ptr = &newplug->args;
 200   return 0;
 201 }
 202
 203 /* Accumulate option arguments for last-loaded plugin, or return
 204    error if none.  */
 205 int
 206 plugin_opt_plugin_arg (const char *arg)
 207 {
 208   plugin_arg_t *newarg;
 209
 210   if (!last_plugin)
 211     return set_plugin_error (_("<no plugin>"));
 212
 213   newarg = xmalloc (sizeof *newarg);
 214   newarg->arg = arg;
 215   newarg->next = NULL;
 216
 217   /* Chain on end to preserve command-line order.  */
 218   *last_plugin_args_tail_chain_ptr = newarg;
 219   last_plugin_args_tail_chain_ptr = &newarg->next;
 220   last_plugin->n_args++;
 221   return 0;
 222 }
 223
 224 /* Create a dummy BFD.  */
 225 bfd *
 226 plugin_get_ir_dummy_bfd (const char *name, bfd *srctemplate)
 227 {
 228   bfd *abfd;
 229
 230   bfd_use_reserved_id = 1;
 231   abfd = bfd_create (concat (name, IRONLY_SUFFIX, (const char *) NULL),
 232                      srctemplate);
 233   if (abfd != NULL)
 234     {
 235       abfd->flags |= BFD_LINKER_CREATED | BFD_PLUGIN;
 236       bfd_set_arch_info (abfd, bfd_get_arch_info (srctemplate));
 237       bfd_set_gp_size (abfd, bfd_get_gp_size (srctemplate));
 238       if (bfd_make_writable (abfd)
 239           && bfd_copy_private_bfd_data (srctemplate, abfd))
 240         {
 241           flagword flags;
 242
 243           /* Create section to own the symbols.  */
 244           flags = (SEC_CODE | SEC_HAS_CONTENTS | SEC_READONLY
 245                    | SEC_ALLOC | SEC_LOAD | SEC_KEEP | SEC_EXCLUDE);
 246           if (bfd_make_section_anyway_with_flags (abfd, ".text", flags))
 247             return abfd;
 248         }
 249     }
 250   einfo (_("could not create dummy IR bfd: %F%E\n"));
 251   return NULL;
 252 }
 253
 254 /* Check if the BFD passed in is an IR dummy object file.  */
 255 static bfd_boolean
 256 is_ir_dummy_bfd (const bfd *abfd)
 257 {
 258   /* ABFD can sometimes legitimately be NULL, e.g. when called from one
 259      of the linker callbacks for a symbol in the *ABS* or *UND* sections.
 260      Likewise, the usrdata field may be NULL if ABFD was added by the
 261      backend without a corresponding input statement, as happens e.g.
 262      when processing DT_NEEDED dependencies.  */
 263   return (abfd
 264           && abfd->usrdata
 265           && ((lang_input_statement_type *)(abfd->usrdata))->claimed);
 266 }
 267
 268 /* Helpers to convert between BFD and GOLD symbol formats.  */
 269 static enum ld_plugin_status
 270 asymbol_from_plugin_symbol (bfd *abfd, asymbol *asym,
 271                             const struct ld_plugin_symbol *ldsym)
 272 {
 273   flagword flags = BSF_NO_FLAGS;
 274   struct bfd_section *section;
 275
 276   asym->the_bfd = abfd;
 277   asym->name = (ldsym->version
 278                 ? concat (ldsym->name, "@", ldsym->version, (const char *) NULL)
 279                 : ldsym->name);
 280   asym->value = 0;
 281   switch (ldsym->def)
 282     {
 283     case LDPK_WEAKDEF:
 284       flags = BSF_WEAK;
 285       /* FALLTHRU */
 286     case LDPK_DEF:
 287       flags |= BSF_GLOBAL;
 288       if (ldsym->comdat_key)
 289         {
 290           char *name = concat (".gnu.linkonce.t.", ldsym->comdat_key,
 291                                (const char *) NULL);
 292           section = bfd_get_section_by_name (abfd, name);
 293           if (section != NULL)
 294             free (name);
 295           else
 296             {
 297               flagword sflags;
 298
 299               sflags = (SEC_CODE | SEC_HAS_CONTENTS | SEC_READONLY
 300                         | SEC_ALLOC | SEC_LOAD | SEC_KEEP | SEC_EXCLUDE
 301                         | SEC_LINK_ONCE | SEC_LINK_DUPLICATES_DISCARD);
 302               section = bfd_make_section_anyway_with_flags (abfd, name, sflags);
 303               if (section == NULL)
 304                 return LDPS_ERR;
 305             }
 306         }
 307       else
 308         section = bfd_get_section_by_name (abfd, ".text");
 309       break;
 310
 311     case LDPK_WEAKUNDEF:
 312       flags = BSF_WEAK;
 313       /* FALLTHRU */
 314     case LDPK_UNDEF:
 315       section = bfd_und_section_ptr;
 316       break;
 317
 318     case LDPK_COMMON:
 319       flags = BSF_GLOBAL;
 320       section = bfd_com_section_ptr;
 321       asym->value = ldsym->size;
 322       /* For ELF targets, set alignment of common symbol to 1.  */
 323       if (bfd_get_flavour (abfd) == bfd_target_elf_flavour)
 324         {
 325           ((elf_symbol_type *) asym)->internal_elf_sym.st_shndx = SHN_COMMON;
 326           ((elf_symbol_type *) asym)->internal_elf_sym.st_value = 1;
 327         }
 328       break;
 329
 330     default:
 331       return LDPS_ERR;
 332     }
 333   asym->flags = flags;
 334   asym->section = section;
 335
 336   /* Visibility only applies on ELF targets.  */
 337   if (bfd_get_flavour (abfd) == bfd_target_elf_flavour)
 338     {
 339       elf_symbol_type *elfsym = elf_symbol_from (abfd, asym);
 340       unsigned char visibility;
 341
 342       if (!elfsym)
 343         einfo (_("%P%F: %s: non-ELF symbol in ELF BFD!\n"), asym->name);
 344       switch (ldsym->visibility)
 345         {
 346         default:
 347           einfo (_("%P%F: unknown ELF symbol visibility: %d!\n"),
 348                  ldsym->visibility);
 349         case LDPV_DEFAULT:
 350           visibility = STV_DEFAULT;
 351           break;
 352         case LDPV_PROTECTED:
 353           visibility = STV_PROTECTED;
 354           break;
 355         case LDPV_INTERNAL:
 356           visibility = STV_INTERNAL;
 357           break;
 358         case LDPV_HIDDEN:
 359           visibility = STV_HIDDEN;
 360           break;
 361         }
 362       elfsym->internal_elf_sym.st_other
 363         = (visibility | (elfsym->internal_elf_sym.st_other
 364                          & ~ELF_ST_VISIBILITY (-1)));
 365     }
 366
 367   return LDPS_OK;
 368 }
 369
 370 /* Register a claim-file handler.  */
 371 static enum ld_plugin_status
 372 register_claim_file (ld_plugin_claim_file_handler handler)
 373 {
 374   ASSERT (called_plugin);
 375   called_plugin->claim_file_handler = handler;
 376   return LDPS_OK;
 377 }
 378
 379 /* Register an all-symbols-read handler.  */
 380 static enum ld_plugin_status
 381 register_all_symbols_read (ld_plugin_all_symbols_read_handler handler)
 382 {
 383   ASSERT (called_plugin);
 384   called_plugin->all_symbols_read_handler = handler;
 385   return LDPS_OK;
 386 }
 387
 388 /* Register a cleanup handler.  */
 389 static enum ld_plugin_status
 390 register_cleanup (ld_plugin_cleanup_handler handler)
 391 {
 392   ASSERT (called_plugin);
 393   called_plugin->cleanup_handler = handler;
 394   return LDPS_OK;
 395 }
 396
 397 /* Add symbols from a plugin-claimed input file.  */
 398 static enum ld_plugin_status
 399 add_symbols (void *handle, int nsyms, const struct ld_plugin_symbol *syms)
 400 {
 401   asymbol **symptrs;
 402   bfd *abfd = handle;
 403   int n;
 404
 405   ASSERT (called_plugin);
 406   symptrs = xmalloc (nsyms * sizeof *symptrs);
 407   for (n = 0; n < nsyms; n++)
 408     {
 409       enum ld_plugin_status rv;
 410       asymbol *bfdsym;
 411
 412       bfdsym = bfd_make_empty_symbol (abfd);
 413       symptrs[n] = bfdsym;
 414       rv = asymbol_from_plugin_symbol (abfd, bfdsym, syms + n);
 415       if (rv != LDPS_OK)
 416         return rv;
 417     }
 418   bfd_set_symtab (abfd, symptrs, nsyms);
 419   return LDPS_OK;
 420 }
 421
 422 /* Get the input file information with an open (possibly re-opened)
 423    file descriptor.  */
 424 static enum ld_plugin_status
 425 get_input_file (const void *handle, struct ld_plugin_input_file *file)
 426 {
 427   ASSERT (called_plugin);
 428   handle = handle;
 429   file = file;
 430   return LDPS_ERR;
 431 }
 432
 433 /* Release the input file.  */
 434 static enum ld_plugin_status
 435 release_input_file (const void *handle)
 436 {
 437   ASSERT (called_plugin);
 438   handle = handle;
 439   return LDPS_ERR;
 440 }
 441
 442 /* Return TRUE if a defined symbol might be reachable from outside the
 443    universe of claimed objects.  */
 444 static inline bfd_boolean
 445 is_visible_from_outside (struct ld_plugin_symbol *lsym,
 446                          struct bfd_link_hash_entry *blhe)
 447 {
 448   struct bfd_sym_chain *sym;
 449
 450   if (link_info.relocatable)
 451     return TRUE;
 452   if (link_info.export_dynamic || !link_info.executable)
 453     {
 454       /* Check if symbol is hidden by version script.  */
 455       if (bfd_hide_sym_by_version (link_info.version_info,
 456                                    blhe->root.string))
 457         return FALSE;
 458       /* Only ELF symbols really have visibility.  */
 459       if (bfd_get_flavour (link_info.output_bfd) == bfd_target_elf_flavour)
 460         {
 461           struct elf_link_hash_entry *el = (struct elf_link_hash_entry *)blhe;
 462           int vis = ELF_ST_VISIBILITY (el->other);
 463           return vis == STV_DEFAULT || vis == STV_PROTECTED;
 464         }
 465       /* On non-ELF targets, we can safely make inferences by considering
 466          what visibility the plugin would have liked to apply when it first
 467          sent us the symbol.  During ELF symbol processing, visibility only
 468          ever becomes more restrictive, not less, when symbols are merged,
 469          so this is a conservative estimate; it may give false positives,
 470          declaring something visible from outside when it in fact would
 471          not have been, but this will only lead to missed optimisation
 472          opportunities during LTRANS at worst; it will not give false
 473          negatives, which can lead to the disastrous conclusion that the
 474          related symbol is IRONLY.  (See GCC PR46319 for an example.)  */
 475       return (lsym->visibility == LDPV_DEFAULT
 476               || lsym->visibility == LDPV_PROTECTED);
 477     }
 478
 479   for (sym = &entry_symbol; sym != NULL; sym = sym->next)
 480     if (sym->name
 481         && strcmp (sym->name, blhe->root.string) == 0)
 482       return TRUE;
 483
 484   return FALSE;
 485 }
 486
 487 /* Get the symbol resolution info for a plugin-claimed input file.  */
 488 static enum ld_plugin_status
 489 get_symbols (const void *handle, int nsyms, struct ld_plugin_symbol *syms,
 490              int def_ironly_exp)
 491 {
 492   const bfd *abfd = handle;
 493   int n;
 494
 495   ASSERT (called_plugin);
 496   for (n = 0; n < nsyms; n++)
 497     {
 498       struct bfd_link_hash_entry *blhe;
 499       asection *owner_sec;
 500       int res;
 501
 502       if (syms[n].def != LDPK_UNDEF)
 503         blhe = bfd_link_hash_lookup (link_info.hash, syms[n].name,
 504                                      FALSE, FALSE, TRUE);
 505       else
 506         blhe = bfd_wrapped_link_hash_lookup (link_info.output_bfd, &link_info,
 507                                              syms[n].name, FALSE, FALSE, TRUE);
 508       if (!blhe)
 509         {
 510           res = LDPR_UNKNOWN;
 511           goto report_symbol;
 512         }
 513
 514       /* Determine resolution from blhe type and symbol's original type.  */
 515       if (blhe->type == bfd_link_hash_undefined
 516           || blhe->type == bfd_link_hash_undefweak)
 517         {
 518           res = LDPR_UNDEF;
 519           goto report_symbol;
 520         }
 521       if (blhe->type != bfd_link_hash_defined
 522           && blhe->type != bfd_link_hash_defweak
 523           && blhe->type != bfd_link_hash_common)
 524         {
 525           /* We should not have a new, indirect or warning symbol here.  */
 526           einfo ("%P%F: %s: plugin symbol table corrupt (sym type %d)\n",
 527                  called_plugin->name, blhe->type);
 528         }
 529
 530       /* Find out which section owns the symbol.  Since it's not undef,
 531          it must have an owner; if it's not a common symbol, both defs
 532          and weakdefs keep it in the same place. */
 533       owner_sec = (blhe->type == bfd_link_hash_common
 534                    ? blhe->u.c.p->section
 535                    : blhe->u.def.section);
 536
 537
 538       /* If it was originally undefined or common, then it has been
 539          resolved; determine how.  */
 540       if (syms[n].def == LDPK_UNDEF
 541           || syms[n].def == LDPK_WEAKUNDEF
 542           || syms[n].def == LDPK_COMMON)
 543         {
 544           if (owner_sec->owner == link_info.output_bfd)
 545             res = LDPR_RESOLVED_EXEC;
 546           else if (owner_sec->owner == abfd)
 547             res = LDPR_PREVAILING_DEF_IRONLY;
 548           else if (is_ir_dummy_bfd (owner_sec->owner))
 549             res = LDPR_RESOLVED_IR;
 550           else if (owner_sec->owner != NULL
 551                    && (owner_sec->owner->flags & DYNAMIC) != 0)
 552             res = LDPR_RESOLVED_DYN;
 553           else
 554             res = LDPR_RESOLVED_EXEC;
 555         }
 556
 557       /* Was originally def, or weakdef.  Does it prevail?  If the
 558          owner is the original dummy bfd that supplied it, then this
 559          is the definition that has prevailed.  */
 560       else if (owner_sec->owner == link_info.output_bfd)
 561         res = LDPR_PREEMPTED_REG;
 562       else if (owner_sec->owner == abfd)
 563         res = LDPR_PREVAILING_DEF_IRONLY;
 564
 565       /* Was originally def, weakdef, or common, but has been pre-empted.  */
 566       else if (is_ir_dummy_bfd (owner_sec->owner))
 567         res = LDPR_PREEMPTED_IR;
 568       else
 569         res = LDPR_PREEMPTED_REG;
 570
 571       if (res == LDPR_PREVAILING_DEF_IRONLY)
 572         {
 573           /* We need to know if the sym is referenced from non-IR files.  Or
 574              even potentially-referenced, perhaps in a future final link if
 575              this is a partial one, perhaps dynamically at load-time if the
 576              symbol is externally visible.  */
 577           if (blhe->non_ir_ref)
 578             res = LDPR_PREVAILING_DEF;
 579           else if (is_visible_from_outside (&syms[n], blhe))
 580             res = def_ironly_exp;
 581         }
 582
 583     report_symbol:
 584       syms[n].resolution = res;
 585       if (report_plugin_symbols)
 586         einfo (_("%P: %B: symbol `%s' "
 587                  "definition: %d, visibility: %d, resolution: %d\n"),
 588                abfd, syms[n].name,
 589                syms[n].def, syms[n].visibility, res);
 590     }
 591   return LDPS_OK;
 592 }
 593
 594 static enum ld_plugin_status
 595 get_symbols_v1 (const void *handle, int nsyms, struct ld_plugin_symbol *syms)
 596 {
 597   return get_symbols (handle, nsyms, syms, LDPR_PREVAILING_DEF);
 598 }
 599
 600 static enum ld_plugin_status
 601 get_symbols_v2 (const void *handle, int nsyms, struct ld_plugin_symbol *syms)
 602 {
 603   return get_symbols (handle, nsyms, syms, LDPR_PREVAILING_DEF_IRONLY_EXP);
 604 }
 605
 606 /* Add a new (real) input file generated by a plugin.  */
 607 static enum ld_plugin_status
 608 add_input_file (const char *pathname)
 609 {
 610   ASSERT (called_plugin);
 611   if (!lang_add_input_file (xstrdup (pathname), lang_input_file_is_file_enum,
 612                             NULL))
 613     return LDPS_ERR;
 614   return LDPS_OK;
 615 }
 616
 617 /* Add a new (real) library required by a plugin.  */
 618 static enum ld_plugin_status
 619 add_input_library (const char *pathname)
 620 {
 621   ASSERT (called_plugin);
 622   if (!lang_add_input_file (xstrdup (pathname), lang_input_file_is_l_enum,
 623                             NULL))
 624     return LDPS_ERR;
 625   return LDPS_OK;
 626 }
 627
 628 /* Set the extra library path to be used by libraries added via
 629    add_input_library.  */
 630 static enum ld_plugin_status
 631 set_extra_library_path (const char *path)
 632 {
 633   ASSERT (called_plugin);
 634   ldfile_add_library_path (xstrdup (path), FALSE);
 635   return LDPS_OK;
 636 }
 637
 638 /* Issue a diagnostic message from a plugin.  */
 639 static enum ld_plugin_status
 640 message (int level, const char *format, ...)
 641 {
 642   va_list args;
 643   va_start (args, format);
 644
 645   switch (level)
 646     {
 647     case LDPL_INFO:
 648       vfinfo (stdout, format, args, FALSE);
 649       putchar ('\n');
 650       break;
 651     case LDPL_WARNING:
 652       vfinfo (stdout, format, args, TRUE);
 653       putchar ('\n');
 654       break;
 655     case LDPL_FATAL:
 656     case LDPL_ERROR:
 657     default:
 658       {
 659         char *newfmt = ACONCAT ((level == LDPL_FATAL ? "%P%F: " : "%P%X: ",
 660                                  format, "\n", (const char *) NULL));
 661         fflush (stdout);
 662         vfinfo (stderr, newfmt, args, TRUE);
 663         fflush (stderr);
 664       }
 665       break;
 666     }
 667
 668   va_end (args);
 669   return LDPS_OK;
 670 }
 671
 672 /* Helper to size leading part of tv array and set it up. */
 673 static void
 674 set_tv_header (struct ld_plugin_tv *tv)
 675 {
 676   size_t i;
 677
 678   /* Version info.  */
 679   static const unsigned int major = (unsigned)(BFD_VERSION / 100000000UL);
 680   static const unsigned int minor = (unsigned)(BFD_VERSION / 1000000UL) % 100;
 681
 682   for (i = 0; i < tv_header_size; i++)
 683     {
 684       tv[i].tv_tag = tv_header_tags[i];
 685 #define TVU(x) tv[i].tv_u.tv_ ## x
 686       switch (tv[i].tv_tag)
 687         {
 688         case LDPT_MESSAGE:
 689           TVU(message) = message;
 690           break;
 691         case LDPT_API_VERSION:
 692           TVU(val) = LD_PLUGIN_API_VERSION;
 693           break;
 694         case LDPT_GNU_LD_VERSION:
 695           TVU(val) = major * 100 + minor;
 696           break;
 697         case LDPT_LINKER_OUTPUT:
 698           TVU(val) = (link_info.relocatable
 699                       ? LDPO_REL
 700                       : link_info.executable ? LDPO_EXEC : LDPO_DYN);
 701           break;
 702         case LDPT_OUTPUT_NAME:
 703           TVU(string) = output_filename;
 704           break;
 705         case LDPT_REGISTER_CLAIM_FILE_HOOK:
 706           TVU(register_claim_file) = register_claim_file;
 707           break;
 708         case LDPT_REGISTER_ALL_SYMBOLS_READ_HOOK:
 709           TVU(register_all_symbols_read) = register_all_symbols_read;
 710           break;
 711         case LDPT_REGISTER_CLEANUP_HOOK:
 712           TVU(register_cleanup) = register_cleanup;
 713           break;
 714         case LDPT_ADD_SYMBOLS:
 715           TVU(add_symbols) = add_symbols;
 716           break;
 717         case LDPT_GET_INPUT_FILE:
 718           TVU(get_input_file) = get_input_file;
 719           break;
 720         case LDPT_RELEASE_INPUT_FILE:
 721           TVU(release_input_file) = release_input_file;
 722           break;
 723         case LDPT_GET_SYMBOLS:
 724           TVU(get_symbols) = get_symbols_v1;
 725           break;
 726         case LDPT_GET_SYMBOLS_V2:
 727           TVU(get_symbols) = get_symbols_v2;
 728           break;
 729         case LDPT_ADD_INPUT_FILE:
 730           TVU(add_input_file) = add_input_file;
 731           break;
 732         case LDPT_ADD_INPUT_LIBRARY:
 733           TVU(add_input_library) = add_input_library;
 734           break;
 735         case LDPT_SET_EXTRA_LIBRARY_PATH:
 736           TVU(set_extra_library_path) = set_extra_library_path;
 737           break;
 738         default:
 739           /* Added a new entry to the array without adding
 740              a new case to set up its value is a bug.  */
 741           FAIL ();
 742         }
 743 #undef TVU
 744     }
 745 }
 746
 747 /* Append the per-plugin args list and trailing LDPT_NULL to tv.  */
 748 static void
 749 set_tv_plugin_args (plugin_t *plugin, struct ld_plugin_tv *tv)
 750 {
 751   plugin_arg_t *arg = plugin->args;
 752   while (arg)
 753     {
 754       tv->tv_tag = LDPT_OPTION;
 755       tv->tv_u.tv_string = arg->arg;
 756       arg = arg->next;
 757       tv++;
 758     }
 759   tv->tv_tag = LDPT_NULL;
 760   tv->tv_u.tv_val = 0;
 761 }
 762
 763 /* Return true if any plugins are active this run.  Only valid
 764    after options have been processed.  */
 765 bfd_boolean
 766 plugin_active_plugins_p (void)
 767 {
 768   return plugins_list != NULL;
 769 }
 770
 771 /* Load up and initialise all plugins after argument parsing.  */
 772 int
 773 plugin_load_plugins (void)
 774 {
 775   struct ld_plugin_tv *my_tv;
 776   unsigned int max_args = 0;
 777   plugin_t *curplug = plugins_list;
 778
 779   /* If there are no plugins, we need do nothing this run.  */
 780   if (!curplug)
 781     return 0;
 782
 783   /* First pass over plugins to find max # args needed so that we
 784      can size and allocate the tv array.  */
 785   while (curplug)
 786     {
 787       if (curplug->n_args > max_args)
 788         max_args = curplug->n_args;
 789       curplug = curplug->next;
 790     }
 791
 792   /* Allocate tv array and initialise constant part.  */
 793   my_tv = xmalloc ((max_args + 1 + tv_header_size) * sizeof *my_tv);
 794   set_tv_header (my_tv);
 795
 796   /* Pass over plugins again, activating them.  */
 797   curplug = plugins_list;
 798   while (curplug)
 799     {
 800       enum ld_plugin_status rv;
 801       ld_plugin_onload onloadfn = dlsym (curplug->dlhandle, "onload");
 802       if (!onloadfn)
 803         onloadfn = dlsym (curplug->dlhandle, "_onload");
 804       if (!onloadfn)
 805         return set_plugin_error (curplug->name);
 806       set_tv_plugin_args (curplug, &my_tv[tv_header_size]);
 807       called_plugin = curplug;
 808       rv = (*onloadfn) (my_tv);
 809       called_plugin = NULL;
 810       if (rv != LDPS_OK)
 811         return set_plugin_error (curplug->name);
 812       curplug = curplug->next;
 813     }
 814
 815   /* Since plugin(s) inited ok, assume they're going to want symbol
 816      resolutions, which needs us to track which symbols are referenced
 817      by non-IR files using the linker's notice callback.  */
 818   orig_notice_all = link_info.notice_all;
 819   orig_callbacks = link_info.callbacks;
 820   plugin_callbacks = *orig_callbacks;
 821   plugin_callbacks.notice = &plugin_notice;
 822   link_info.notice_all = TRUE;
 823   link_info.callbacks = &plugin_callbacks;
 824
 825   return 0;
 826 }
 827
 828 /* Call 'claim file' hook for all plugins.  */
 829 static int
 830 plugin_call_claim_file (const struct ld_plugin_input_file *file, int *claimed)
 831 {
 832   plugin_t *curplug = plugins_list;
 833   *claimed = FALSE;
 834   if (no_more_claiming)
 835     return 0;
 836   while (curplug && !*claimed)
 837     {
 838       if (curplug->claim_file_handler)
 839         {
 840           enum ld_plugin_status rv;
 841           called_plugin = curplug;
 842           rv = (*curplug->claim_file_handler) (file, claimed);
 843           called_plugin = NULL;
 844           if (rv != LDPS_OK)
 845             set_plugin_error (curplug->name);
 846         }
 847       curplug = curplug->next;
 848     }
 849   return plugin_error_p () ? -1 : 0;
 850 }
 851
 852 void
 853 plugin_maybe_claim (struct ld_plugin_input_file *file,
 854                     lang_input_statement_type *entry)
 855 {
 856   int claimed = 0;
 857
 858   /* We create a dummy BFD, initially empty, to house whatever symbols
 859      the plugin may want to add.  */
 860   file->handle = plugin_get_ir_dummy_bfd (entry->the_bfd->filename,
 861                                           entry->the_bfd);
 862   if (plugin_call_claim_file (file, &claimed))
 863     einfo (_("%P%F: %s: plugin reported error claiming file\n"),
 864            plugin_error_plugin ());
 865   /* fd belongs to us, not the plugin; but we don't need it.  */
 866   close (file->fd);
 867   if (claimed)
 868     {
 869       /* Discard the real file's BFD and substitute the dummy one.  */
 870
 871       /* BFD archive handling caches elements so we can't call
 872          bfd_close for archives.  */
 873       if (entry->the_bfd->my_archive == NULL)
 874         bfd_close (entry->the_bfd);
 875       entry->the_bfd = file->handle;
 876       entry->claimed = TRUE;
 877       bfd_make_readable (entry->the_bfd);
 878     }
 879   else
 880     {
 881       /* If plugin didn't claim the file, we don't need the dummy bfd.
 882          Can't avoid speculatively creating it, alas.  */
 883       bfd_close_all_done (file->handle);
 884       entry->claimed = FALSE;
 885     }
 886 }
 887
 888 /* Call 'all symbols read' hook for all plugins.  */
 889 int
 890 plugin_call_all_symbols_read (void)
 891 {
 892   plugin_t *curplug = plugins_list;
 893
 894   /* Disable any further file-claiming.  */
 895   no_more_claiming = TRUE;
 896
 897   while (curplug)
 898     {
 899       if (curplug->all_symbols_read_handler)
 900         {
 901           enum ld_plugin_status rv;
 902           called_plugin = curplug;
 903           rv = (*curplug->all_symbols_read_handler) ();
 904           called_plugin = NULL;
 905           if (rv != LDPS_OK)
 906             set_plugin_error (curplug->name);
 907         }
 908       curplug = curplug->next;
 909     }
 910   return plugin_error_p () ? -1 : 0;
 911 }
 912
 913 /* Call 'cleanup' hook for all plugins at exit.  */
 914 void
 915 plugin_call_cleanup (void)
 916 {
 917   plugin_t *curplug = plugins_list;
 918   while (curplug)
 919     {
 920       if (curplug->cleanup_handler && !curplug->cleanup_done)
 921         {
 922           enum ld_plugin_status rv;
 923           curplug->cleanup_done = TRUE;
 924           called_plugin = curplug;
 925           rv = (*curplug->cleanup_handler) ();
 926           called_plugin = NULL;
 927           if (rv != LDPS_OK)
 928             set_plugin_error (curplug->name);
 929           dlclose (curplug->dlhandle);
 930         }
 931       curplug = curplug->next;
 932     }
 933   if (plugin_error_p ())
 934     info_msg (_("%P: %s: error in plugin cleanup (ignored)\n"),
 935               plugin_error_plugin ());
 936 }
 937
 938 /* To determine which symbols should be resolved LDPR_PREVAILING_DEF
 939    and which LDPR_PREVAILING_DEF_IRONLY, we notice all the symbols as
 940    the linker adds them to the linker hash table.  Mark those
 941    referenced from a non-IR file with non_ir_ref.  We have to
 942    notice_all symbols, because we won't necessarily know until later
 943    which ones will be contributed by IR files.  */
 944 static bfd_boolean
 945 plugin_notice (struct bfd_link_info *info,
 946                struct bfd_link_hash_entry *h,
 947                bfd *abfd,
 948                asection *section,
 949                bfd_vma value,
 950                flagword flags,
 951                const char *string)
 952 {
 953   if (h != NULL)
 954     {
 955       bfd *sym_bfd;
 956
 957       /* No further processing if this def/ref is from an IR dummy BFD.  */
 958       if (is_ir_dummy_bfd (abfd))
 959         return TRUE;
 960
 961       /* Making an indirect symbol counts as a reference unless this
 962          is a brand new symbol.  */
 963       if (bfd_is_ind_section (section)
 964           || (flags & BSF_INDIRECT) != 0)
 965         {
 966           if (h->type != bfd_link_hash_new)
 967             {
 968               struct bfd_link_hash_entry *inh;
 969
 970               h->non_ir_ref = TRUE;
 971               inh = bfd_wrapped_link_hash_lookup (abfd, info, string, FALSE,
 972                                                   FALSE, FALSE);
 973               if (inh != NULL)
 974                 inh->non_ir_ref = TRUE;
 975             }
 976         }
 977
 978       /* Nothing to do here for warning symbols.  */
 979       else if ((flags & BSF_WARNING) != 0)
 980         ;
 981
 982       /* Nothing to do here for constructor symbols.  */
 983       else if ((flags & BSF_CONSTRUCTOR) != 0)
 984         ;
 985
 986       /* If this is a ref, set non_ir_ref.  */
 987       else if (bfd_is_und_section (section))
 988         h->non_ir_ref = TRUE;
 989
 990       /* Otherwise, it must be a new def.  Ensure any symbol defined
 991          in an IR dummy BFD takes on a new value from a real BFD.
 992          Weak symbols are not normally overridden by a new weak
 993          definition, and strong symbols will normally cause multiple
 994          definition errors.  Avoid this by making the symbol appear
 995          to be undefined.  */
 996       else if (((h->type == bfd_link_hash_defweak
 997                  || h->type == bfd_link_hash_defined)
 998                 && is_ir_dummy_bfd (sym_bfd = h->u.def.section->owner))
 999                || (h->type == bfd_link_hash_common
1000                    && is_ir_dummy_bfd (sym_bfd = h->u.c.p->section->owner)))
1001         {
1002           h->type = bfd_link_hash_undefweak;
1003           h->u.undef.abfd = sym_bfd;
1004         }
1005     }
1006
1007   /* Continue with cref/nocrossref/trace-sym processing.  */
1008   if (h == NULL
1009       || orig_notice_all
1010       || (info->notice_hash != NULL
1011           && bfd_hash_lookup (info->notice_hash, h->root.string,
1012                               FALSE, FALSE) != NULL))
1013     return (*orig_callbacks->notice) (info, h,
1014                                       abfd, section, value, flags, string);
1015   return TRUE;
1016 }
1017
1018 /* Return true if bfd is a dynamic library that should be reloaded.  */
1019
1020 bfd_boolean
1021 plugin_should_reload (bfd *abfd)
1022 {
1023   return ((abfd->flags & DYNAMIC) != 0
1024           && bfd_get_flavour (abfd) == bfd_target_elf_flavour
1025           && bfd_get_format (abfd) == bfd_object
1026           && (elf_dyn_lib_class (abfd) & DYN_AS_NEEDED) != 0);
1027 }